Question

I’m beginning to explore programming in objective-c and I wrote a few lines of code for a command line tool. It works but now I’m trying to rewrite it in Cocoa application and I have some problems. This is the working code of the single line tool:

 //Formattazione delle date preimpostate
    NSDateFormatter *formatoData = [[NSDateFormatter alloc] init];
    [formatoData setDateFormat:@"dd/MM/yyyy"];

    //Definizione della data di inizio e della data di fine
    NSDate * dataInizio = [formatoData dateFromString:datePicker];

    //Risultato
    NSString *risultato=[dataInizio descriptionWithCalendarFormat:@"%w" timeZone:nil locale:nil];

    //Output
    NSLog(@"Il giorno impostato è %@", risultato);

To create the Cocoa application, I have created an objective-C class I called VisualizzaClasse.
VisualizzaClasse.h:

#import <Foundation/Foundation.h>

@interface VisualizzaClasse : NSObject
{
    IBOutlet NSDatePicker *datePicker;
    IBOutlet NSTextView *textView;}
- (IBAction)mostraRisultato:(id)sender;

@end

VisualizzaClasse.m:

#import "VisualizzaClasse.h"

@implementation VisualizzaClasse

- (IBAction)mostraRisultato:(id)sender;
{
     //Formattazione delle date preimpostate

        NSDateFormatter *formatoData = [[NSDateFormatter alloc] init];
        [formatoData setDateFormat:@"dd/MM/yyyy"];
        //Definizione della data di inizio e della data di fine
   NSDate * dataInizio = [formatoData dateFromString:datePicker];

        //Risultato
        NSString *risultato=[dataInizio descriptionWithCalendarFormat:@"%w" timeZone:nil locale:nil];

    [textView insertText:[NSString stringWithFormat:@"%@ \n", risultato]];
}


@end

The interface is composed of a DatePicker, TextView and by a button.I can not make the DatePicker replace dateFromString.The error is: incompatible pointer type sending ‘NSDatePicker _strong *’ to parameter of type ‘NSString *’, at the line:

NSDate * dataInizio = [formatoData dateFromString:datePicker];

Can anyone help me?

Answer 1

I’m assuming you have the NSDatePicker correctly hooked up in InterfaceBuilder so it is connected to DatePicker.

If so, you should be able to assign as follows:

NSDate * unformattedDate = [ datePicker dateValue ];

And then do your formatting as before, using unformattedDate as the input to your formatter.